In recent years, there are growing fears about health hazards of materials of animal origin, and regulations for such materials are being tightened, which gives rise to stronger interest in materials of plant origin in cosmetic industries. On the other hand, serious problems are arising, such as acceleration of ageing by oxidation of active oxygen taken into or generated within the body, and skin coloration by UV rays or carcinogenicity thereof.
Cosmetics, dermatological compositions, and food compositions are suffering from oxidation or peroxidation of oils and fats contained in various materials thereof, during processing, manufacture, storage, or preservation of such articles. Unsaturated fatty acids contained in oils and fats, such as linoleic and linolenic acids, are known to be particularly prone to peroxidation by atmospheric oxygen to generate lipid peroxides, free radicals, or even carcinogenic substances (see, for example, “Shokuhin no Housou” Vol. 17, p 106, 1986). Oxidation and peroxidation cause change of the products in appearance, such as coloration, discoloration, denaturalizaton, or abnormal odor, or in quality, such as decrease in effective nutritional value or effectiveness. Further denaturalization may cause generation of toxic substances, which results in deterioration of product quality.
In order to inhibit such oxidation and peroxidation of unsaturated fatty acids, and to prevent deterioration of product quality, various antioxidants have conventionally been used. Antioxidants act on peroxide radicals, which are generated in oxidation, to terminate chain oxidation, or alternatively act on free radicals to terminate oxidative reaction. Commonly used antioxidants are synthetic antioxidants, such as butylhydroxyanisol (BHA) and butylhydroxytoluene (BHT). Recently, however, effects and safety of synthetic antioxidants on the human body have come to be questioned as their use expands, and consumers are presenting growing rejections.
This situation leads to rapidly growing expectation for natural antioxidants. However, known natural antioxidants, such as natural vitamin E (α-tocopherol), vitamin C, and the like, have disadvantages in that their activity cannot be maintained stably for a prolonged period of time. Accordingly, there is a strong demand for natural antioxidants having strong antioxidative activity as well as long-term stability in the activity.
In the cosmetic industry, whitening effect on skin has been an important issue, which has been attracting various proposals to date. Causes of pigmentation, such as skin coloration or age spots, may be categorized roughly into intrinsic factors such as metabolic defects in living organism, and extrinsic factors such as UV rays. Pigmentation caused by the latter extrinsic factors is more common, wherein UV rays stimulate melanocytes to activate the same, which in turn activates tyrosinase to induce skin pigmentation. Inhibition of the melanocyte activity to thereby inhibit generation of tyrosinase and melanin pigment results in prevention of pigmentation such as skin coloration or age spots, and accordingly maintenance of white skin. Recently, UV dose is increasing due to ozone depletion, which further stimulates consumer's demand for measures against UV, and safe and effective whitening agents.
Camu camu fruit is rich in vitamin C, and is now recognized as the most vitamin C-rich plant. The fruit of camu camu is commercially sold in South America as cosmetics or food, and is recently imported and sold also in Japan as a food material. Vitamin C is the only component of the fruit of camu camu that is known to have antioxidative effect and whitening effect.